Art of producing gelatin and glue



Patented July 14, 1942 UNETED STT 2,290,081 ART OF PRODUCING GELATIN ANDGLUE Leo Wallerstein,

New York, N. Y., and Julius Pfannmullcr, North Plainfield, N. J.,assignors to Wallerstein Company, Inc.,

New York, N. Y.,

a corporation of New York No Drawing. Application July 2'7, 1938, SerialNo. 221,642

6 Claims. (Cl. 260-118) This invention relates to the art of producinggelatin and glue.

In producing gelatin and glue from raw material of animal origin, suchas bones, skins, cartilage and the like, it is the usual procedure,after removal of inorganic substances, such as tricalcium phosphate,etc., to steep the raw material, which contains collagen, in milk oflime. Ordinarily, these lime liquors are changed or renewed from time totime and the treatment is continued for a considerable length of time.

In the case of so-called dried buffalo pieces, for instance, the rawmaterial is steeped in lime liquors until the material is sufiicientlyswollen and bleached and is no longer firm, but soft. This ordinarilyrequires from at least four weeks to several months.

After the lime liquor treatment, the raw material is washed and de-limedor neutralized with suitable acids. It is then subjected to a so-calledcooking process by which a solution of gelatin is obtained. Thissolution is subjected to various filtering and cleaning operations andthen evaporated and dried to obtain the finished product, gelatin orglue.

The liming or pre-cooking treating is of great importance because thecollagen and other tissues must be ripened or chemically digested tosuch a form that, in the subsequent cooking operation, such tissueseasily go into solution without leaving too much residue and Withoutnecessitating excessive cooking temperatures.

It is an object of the present invention to provide a process oftreating raw materials of animal origin for the production of gelatin orglue such that the time required for the requisite ripening or chemicaldigestion is materially reduced.

It is a further object of the invention to provide such a process thatnot only attains the end just referred to but also makes possible ahigher yield and a better product.

In carrying out the present invention we add to the usual lime liquor arelatively small amount of a reducing sulphur-oxygen compound. Compoundssuitable for carrying out the process of the invention are characterizedby being stable in dry condition and having a substantially greaterreducing power in solution than that of the sulphates, sulphites,sulphides or thio-sulphates. While various such compounds may be used,the invention is carried out to what is now considered the bestadvantage by the use of compounds of the class of hydrosulphites andsulphoxylates and corresponding organic compounds of sulphur and oxygen.We have found, for example, that sodium hydrosulphite, sodiumsulphoxylate, sodium formaldehyde sulphoxylate or zinc calciumhydrosulphite are suitable and satisfactory.

In this connection, we are aware that there is some existing confusionin text books and chemical dictionaries with respect to the termshydrosulphite and hyposulphite. However, in the present applicationsodium hydrosulphite means the compound Na2S2O4 and in referring tohydrosulphites in general we refer to salts of hydrosulphurous acid(H2S2O4) If, in the pre-cooking treatment, only one lime liquor isutilized, the sodium hydrosulphite or other compound is, of course,added to that liquor. If the lime liquor is changed during the digestionor pre-cooking period, the sodium hydrosulphite or other compound may beadded to one, some or all of the lime baths, depending on the rawmaterials used and the desired time interval for obtaining properdigestion. If several renewals of lime liquor are put into effect,addition of the sodium hydrosulphite or other compound to one bath willmaterially reduce the period necessary for obtaining proper digestion.Addition to more than one lime liquor further shortens the digestionperiod, for a given raw material.

While the amount of sodium hydrosulphite or other compound added mayvary within a considerable range, about one half of one per cent (0.5%)based on the dry weight of hides treated has been found suitable andsatisfactory.

If sodium hydrosulphite is used, it may be added in ordinary commercialform or its presence may be obtained by adding a mixture of materialsincluding sodium hydrosulphite. An example of such a mixture isdisclosed and claimed in an application filed by us of even dateherewith (Ser. No. 221,643), said mixture including sodium hydrosulphiteand one or more agents which tend to stabilize the hydrosulphite againstthe deteriorating effects of moist and damp air. If a mixture is used,enough of the mixture should be added to give substantially the sameamount of sodium hydrosulphite as would be obtained if the latter wereadded in commercial form.

The hide-water ratio and the amount of lime used may conveniently be inaccordance with usual practice. For example, a hide-water ratio of 1:4(by weight) and about 10% lime, based on skin dry weight, have beenfound suitable and satisfactory.

After the raw material has been properly ripened or digested it iswashed, neutralized and cooked and the resulting gelatin solution isfiltered, cleaned, evaporated and dried in the usual manner to producegelatin or glue.

Whether the hydrosulphite or other compound attacks the collagenoustissues and, if so, what the mechanism of the attack may be, has notbeen fully determined. The fact remains that when a compound of theclass referred to is added to one or more of the lime liquors, thepre-cooking or digesting treatment is materially accelerated as to therequisite time involved; the ultimate yield is higher; and the gelatinor glue has a lighter and more desirable color, as compared to resultsobtained when no such compound is added.

The following procedures example:

are given by way of Example I Soak 100 pounds dried hides, i. e.,so-called bufialo pieces, in water at 60-70 F. for one day.

Transfer the hides to a bath consisting of 400 pounds (48 gallons) ofwater containing pounds of lime. Add one half pound sodiumhydrosulphite. Leave the skins in this liquor at room temperature (6070F.) for one week.

Transfer to a new lime liquor consisting of 400 pounds water and 10pounds lime and leave for one week. Transfer to a new and similar limeliquor and leave for 6 weeks.

At the end of this period the raw material is ready for cooking andsubsequent operations.

Example II Soak 283 pounds of bufialo pieces in Water at 60-70 F. forone day.

Transfer the hides to a bath consisting of 1130 pounds water (136gallons) containing 28 pounds lime. Leave for 3 days.

Transfer the hides to a new liquor containing 1130 pounds water, 28pounds lime and 1.4 pounds sodium hydrosulphite. Leave for 16 days.

Transfer the hides to a fresh liquor identical in composition with theprevious one and leave for 3 weeks.

At the end of this period the raw material is ready for the cooking andsubsequent operations.

Example III Soak 100 pounds buifalo pieces in water at 60-'70 F. for oneday.

Put soaked pieces in a liquor consisting of 400 pounds water and 10pounds lime. Leave for 2 days.

Transfer to a new lime liquor of same composition and add one half poundsodium hydrosulphite. Leave for about one week.

Transfer to a new lime liquor of the same composition as the first. Stiroccasionally.

After a few weeks the raw material is ready for cooking.

Example I V Follow the procedure of Example III except that the sodiumhydrosulphite is added to the third bath instead of the second.

What is claimed is:

l. A process of accelerating the ripening and digesting ofcollagen-containing raw material of animal origin in lime liquor, forthe preparation of gelatin or glue, which comprises adding ahydrosulphite to the lime liquor.

2. A process of accelerating the ripening and digesting ofcollagen-containing raw materal of animal origin in lime liquor, for thepreparation of gelatin or glue, which comprises adding sodiumhydrosulphite to the lime liquor.

3. In the process of accelerating the ripening and digestingcollagen-containing raw material of animal origin in a plurality of limebaths, for the preparation of gelatin or glue, the improvement whichcomprises adding a hydrosulphite to at least one of the lime baths.

4. In the process of accelerating the ripening and digestingcollagen-containing raw material of animal origin in a plurality of limebaths, for the preparation of gelatin or glue, the improve ment whichcomprises adding sodium hydrosulphite to at least one of the lime baths.

5. A process of accelerating the ripening and digesting ofcollagen-containing raw material of animal origin in lime liquor, forthe preparation of gelatin or glue, which comprises adding sodiumhydrosulphite in an amount approximating one-half of one per cent basedon the dry weight of said raw material.

6. A process of accelerating the ripening and digesting ofcollagen-containing raw materials of animal origin in lime liquor, inthe preparaing to the lime liquor a compound selected from the classconsisting of hydrosulphites and sulphoxylates.

LEO WALLERSTEIN. JULIUS PFANNMULLER.

